Information Systems Engineering

Lecture Outline Information Systems Architecture Information System Architecture components Information Engineering Phases of Information Engineering Features of Information Engineering 2INFORMATION SYSTEM ENGINEERING

Information Systems(IS) Planning Introduction : Sometimes called “enterprise-wide computing” or “Information Architecture” Scope of (IS Planning) is now the entire organization There is a problem: isolated groups in an organization start their own databases and it becomes impossible to find out who has what information, where there are overlaps, and to assess the accuracy of the information To support enterprise-wide computing, there must be enterprise-wide information planning One framework for thinking about and planning for enterprise-wide computing is an Information Systems Architecture or ISA Most organizations do NOT have such an architecture 3INFORMATION SYSTEM ENGINEERING

Information Systems Architecture (ISA) An ISA is a “conceptual blueprint or plan that expresses the desired future structure for information systems in an organization” It provides a “context within which managers throughout the organization can make consistent decisions concerning their information systems” 4INFORMATION SYSTEM ENGINEERING

Benefits of ISA – Provides a basis for strategic planning of IS – Provides a basis for communicating with top management and a context for budget decisions concerning IS – Provides a unifying concept for the various stakeholders in information systems. – Communicates the overall direction for information technology and a context for decisions in this area – Helps achieve information integration when systems are distributed – Provides a basis for evaluating technology options (for example, downsizing and distributed processing) 5INFORMATION SYSTEM ENGINEERING

Zachman ISA Framework components – Data The “What” of the information system – Process The “How” of the information system – Network The “Where” of the information system – People Who performs processes and are the source and receiver of data and information. – Events and Points in time When processes are performed – Reasons Why: For events and rules that govern processing 6INFORMATION SYSTEM ENGINEERING

Roles of Data, Process and Network Six perspectives of the Data, Process and Network components – Business scope (Owner) – Business model (Architect) – Information systems model (Designer) – Technology model (Builder) – Technology definition (Contractor) – Information system (User) 7INFORMATION SYSTEM ENGINEERING

Explanation of the components Data Process Network 1. Enterprise Scope (Owner) List of entities important to the business List of processes or functions that the business performs List of locations in which the business operates 8INFORMATION SYSTEM ENGINEERING

Explanation of the components (contd….) Data Process Network 2. Enterprise Model (Architect) Business entities and their relationships Function and process decomposition Communications links between business locations 9INFORMATION SYSTEM ENGINEERING

Explanation of the components (contd….) Data Process Network 3. Information System Model (Designer) Model of the business data and their relationships (ERD in Database design) Flows between application processes Distribution Network 10INFORMATION SYSTEM ENGINEERING

Explanation of the components (contd….) Data Process Network 4. Technology Constrained Model (Builder) Database Design (logical) Process specifications Database Design 11INFORMATION SYSTEM ENGINEERING

Explanation of the components (contd….) Data Process Network 5. Technology Definition/ Detailed Representations (Contractor) Database Schema and subschema definition Program Code and control blocks Configuration definition/ Network Architecture 12INFORMATION SYSTEM ENGINEERING

Explanation of the components (contd….) Data Process Network 6. Functioning Enterprise (User) Implemented Database and information Current System Configuration Implemented Application Programs 13INFORMATION SYSTEM ENGINEERING

Information Engineering Information Engineering: “an interlocking set of formal techniques in which enterprise models, data models and process models are built... and are used to create and maintain Information Systems” James Martin (1986) 14INFORMATION SYSTEM ENGINEERING

Object-oriented concepts Database technology (Relational, Hierarchical, Network ) Data oriented methodology Data analysis and data management Full lifecycle coverage Focus on data and activities The use of tools such as CASE( Computer Aided Software Engineering ) Note: CASE tools are a class of software that automate many of the activities involved in various life cycle phasessoftwarelife cycle Information Engineering (contd….) 15INFORMATION SYSTEM ENGINEERING

Strategic data models Alignment of information systems planning with strategic business planning Process modeling techniques top-down analysis and development of organization's applications Information Engineering (contd….) 16INFORMATION SYSTEM ENGINEERING

1. Information strategy planning to build an information and technology architecture to support business strategy and objectives 2. Business area analysis to identify data and function requirements of each business area 3. Individual systems planning 4. Individual Systems design to complete logical specifications for a system and convert these into physical design specifications 5. Construction to generate code, test, and install the system 6. Cutover Major Phases of Information Engineering 17INFORMATION SYSTEM ENGINEERING

Phase 1 - information strategy planning: business mission, objectives, CSFs, performance measurements, organization structure, current situation construct corporate data model determine major business area/functions determine: – information architecture (global entities and business area/functions ) – technical architecture (technology: HW/SW/Comm.) – information strategy plan (priorities) 18INFORMATION SYSTEM ENGINEERING

Phase 2 - Business Area Analysis The Business Area Analysis must help in the following: identify and model in detail the fundamental data and activities required to support a business area ensure that requirements enable business area’s goals and CSFs to be supported ensure that requirements are independent of : – technology – current systems and procedures – current organizational structure a high-level executive sponsor is necessary 19INFORMATION SYSTEM ENGINEERING

Business area analysis: steps extract the relevant entity relationship model and business- function decomposition models identify relevant departments, locations, business goals, CSFs create a preliminary data model: identify events, entity life cycles, initial attributes create a preliminary process model: decompose the functions into processes model data and processes of existing systems for comparison involve all affected end-users in iteratively building: a detailed data model, a detailed process model, entity / process matrices identify and priorities system development projects 20INFORMATION SYSTEM ENGINEERING

Business area analysis: techniques data model entity relationship modeling attribute collection normalization canonical synthesis process model process decomposition models process dependency diagrams data and activity interaction entity lifecycles process / entity matrix 21INFORMATION SYSTEM ENGINEERING

Information engineering: phases 3 and 4 Phase 3 - individual systems planning Although it is individual but we have to use JRP (Joint Requirement Planning) for individual systems planning Phase 4 - individual system design concerned with how selected processes in the business are implemented in procedures and how these procedures work direct end-user involvement is essential identify reusable procedures use prototyping use JAD (Joint Application Design) 22INFORMATION SYSTEM ENGINEERING

System design techniques 1.prototyping 2.detailed process models: procedure design using access path and volumes analysis, dialogue flows and menu structures, 3.physical database design, file design, 4.screen displays 5.menu flows 6.report layouts 7.batch procedures and software 8.design verification and testing 23INFORMATION SYSTEM ENGINEERING

Phase 5 - construction: technical design, create physical databases create modules and programs, unit testing system testing, documentation Phase 6 - cutover: conversion final testing conduct training install the system, review implementation Information engineering: phases 5 and 6 24INFORMATION SYSTEM ENGINEERING

Information Engineering Features organization-wide perspective aligned with strategic business planning Comprehensive (complete, full) emphasis on user involvement e.g. JAD, JRP evolves by incorporating new techniques, concepts, technologies e.g. object-oriented concepts emphasis on automation e.g. 4GLs, I-CASE, prototypes 25INFORMATION SYSTEM ENGINEERING

primarily for database transaction processing systems flexible paths through the methodology e.g. reverse engineering and re-engineering Information Engineering Features (Contd….) 26INFORMATION SYSTEM ENGINEERING

References Avison, D.E. & Fitzgerald, G. (2003). Information Systems Development: Methodologies, Techniques and Tools. (3rd ed), McGraw-Hill, London. Chapters 20.1, INFORMATION SYSTEM ENGINEERING